Generally, the widely-used peripheral input device of a computer system includes for example a mouse device, a keyboard device, a trackball device, or the like. Via the keyboard device, characters and symbols can be inputted into the computer system directly. As a consequence, most users and most manufacturers of input devices pay much attention to the development of keyboard devices. The keyboard devices are classified into two types, i.e. the keyboard devices for desktop computers and the keyboard modules for notebook computers.
FIG. 1 is a schematic top view illustrating the outer appearance of a conventional keyboard module. As shown in FIG. 1, there are plural first keys 11 and plural second keys 12 on a surface of the conventional keyboard module 1. In comparison with the first keys 11, each of the second keys 12 further comprises an indication lampshade 120. When the first key 11 or the second key 12 is depressed by the user's finger, a corresponding signal is generated to the computer. According to the signal, the computer executes the function corresponding to the depressed key. For example, the conventional keyboard module 1 is a keyboard device for a notebook computer, and one of the second keys 12 is a Caps Lock key.
Hereinafter, the inner structure of the conventional keyboard module will be illustrated with reference to FIG. 2. FIG. 2 is a schematic side view illustrating a portion of the conventional keyboard module. In addition to the first keys 11 and the second keys 12, the conventional keyboard module 1 further comprises a membrane switch circuit member 13, a bottom plate 14 and a light-emitting element 15. Firstly, the structures of the first keys 11 and the second keys 12 will be described. Each first key 11 comprises a first keycap 111, a first scissors-type connecting element 112 and a first elastic element 113. Each second key 12 comprises a second keycap 121, a second scissors-type connecting element 122 and a second elastic element 123. The first scissors-type connecting element 112 of the first key 11 is used for connecting the first keycap 111 and the bottom plate 14 and allowing the first keycap 111 to be moved upwardly or downwardly. The first elastic element 113 is penetrated through the first scissors-type connecting element 112. Moreover, both ends of the first elastic element 113 are contacted with the first keycap 111 and the membrane switch circuit member 13, respectively. The first scissors-type connecting element 112 has a symmetrical structure. That is, the structure of a first side (e.g., the left side) of the first scissors-type connecting element 112 and the structure of a second side (e.g., the right side) of the first scissors-type connecting element 112 are identical.
Each second key 12 comprises a second keycap 121, a second scissors-type connecting element 122 and a second elastic element 123. The second scissors-type connecting element 122 of the second key 12 is used for connecting the second keycap 121 and the bottom plate 14 and allowing the second keycap 121 to be moved upwardly or downwardly. The second elastic element 123 is penetrated through the second scissors-type connecting element 122. Moreover, both ends of the second elastic element 123 are contacted with the second keycap 121 and the membrane switch circuit member 13, respectively. The second scissors-type connecting element 122 also has a symmetrical structure. That is, the structure of a first side (e.g., the left side) of the second scissors-type connecting element 122 and the structure of a second side (e.g., the right side) of the second scissors-type connecting element 122 are identical.
The membrane switch circuit member 13 comprises an upper wiring board 131, a spacer layer 132, and a lower wiring board 133. The upper wiring board 131 has plural upper contacts 1311. The spacer layer 132 is disposed under the upper wiring board 131, and comprises plural perforations 1321 corresponding to the plural upper contacts 1311. The lower wiring board 133 is disposed under the spacer layer 132, and comprises plural lower contacts 1331 corresponding to the plural upper contacts 1311. The plural lower contacts 1331 and the plural upper contacts 1311 are collectively defined as plural key switches 134. When the first keycap 111 is depressed and moved downwardly to push the first elastic element 113, the corresponding key switch 134 is triggered. The way of depressing the second keycap 112 is similar to the way of depressing the first keycap 111, and is not redundantly described herein. As shown in FIG. 2, the light-emitting element 15 corresponds to the second key 12. For example, the light-emitting element 15 is disposed under the second keycap 121. The light-emitting element 15 emits a light beam and projecting the light beam to the indication lampshade 120. Consequently, an illuminating function is achieved.
However, since the keyboard module 1 has the light-emitting element 15 corresponding to the second key 12, the light-emitting element 15 is covered or sheltered by the second scissors-type connecting element 122. Consequently, the illuminating efficacy of the light-emitting element 15 is adversely affected by the second scissors-type connecting element 122. For solving this drawback, a smaller scissors-type connecting element is used for preventing the light-emitting element 15 from being sheltered. The illuminating efficacy of the light-emitting element 15 is not adversely affected by the smaller scissors-type connecting element. However, the smaller scissors-type connecting element cannot stably support the second keycap 121. When the second keycap 121 is depressed by the user, the second keycap 121 is synchronously moved with the smaller scissors-type connecting element. Since the movement of the second key is unstable, the hand feel of depressing the key is usually unsatisfied.
Therefore, there is a need of providing a keyboard module and keys with stabilized keycaps and enhanced illuminating efficiency.